In recent years, ultrasonic waves diagnostic apparatus for medical echo imaging analysis uses a 2-D array ultrasonic probe capable of diagnosing of a three-dimensional motion picture in real-time. In the 2-D array ultrasonic probe, ultrasonic waves are transmitted from a transducer arranged in a 2-D array form, and the reflected ultrasonic waves are received by the transducer. Detected signals are sent to a main body of an inspection apparatus and through a cable, so that the signals are subjected to image processing and used for diagnosis and the like.
In a convex-type 2-D array ultrasonic probe, there are transducers for several thousands piezoelectric elements are arranged in a 2-D convex array form, and a flexible wire substrate (FPC) is used to connect the transducer and the circuit board substrate (PCB). In FPC, electrodes are arranged alternately on a front surface and a back surface in the plan view of a PCB, so that wires are drawn from the transducer with the shortest distance from both surfaces of PCB and at the highest density (FIG. 3A).
When the electrodes of FPC is connected to a electrodes of PCB, an anisotropic conductive film (ACF) is used. At this occasion, the ACF is provided on the electrode pad on the front surface of the PCB, and the FPC is arranged thereon. In addition, for example, a polytetra fluoroethylene (PTFE) film (sheet material with a high degree of heat resistance and releasing property) is provided thereon, and the resin sheet is attached thereon by thermocompressive bonding using a heat tool. In this configuration, it is connected with the electrodes of the FPC and the electrodes of the PCB with the particles contained in ACF electrically. Likewise, an electrodes of FPC is also connected to electrodes provided on the back surface of the PCB.
The above ultrasonic probe involves the following problems. That is, there is a certain space between an FPC connected to a front surface PCB side and an FPC adjacent thereto. When the FPC at the back surface side is arranged at a position corresponding to this space, the rigidity of the PCB is insufficient for attachment by thermocompressive bonding using a heat tool. As a result, the FPC cannot follow deformation of the PCB, which reduces the flatness of the thermocompressive bonding surface. Therefore, the pressurizing force is insufficient, and this may cause defective of electric connection.
Accordingly, it is an object to provide an ultrasonic probe and a method for manufacturing the ultrasonic probe capable of solving the shortage of the pressurizing force and ensuring the connection by sufficiently ensuring the flatness of the thermocompressive bonding surface.